"If military tension is aggravated, then clashes could crop up that could lead to a repeat of armed incidents... of June 25, 1950," the Korean Central News Agency (KCNA) said in a statement distributed Thursday.
A three-year war hit the peninsula in 1950, and a truce was signed in 1953, but a peace treaty has yet to be concluded.
North Korea blames new South Korean leader Lee Myung-bak, who assumed office in February, for the current situation, saying he had put inter-Korean relations back 10 years.
In particular, North Korea has accused Myung-bak of rejecting all reconciliation and cooperation agreements between Seoul and Pyongyang, which were reached with difficulty by his Liberal Democrat predecessors.
The KCNA called on South Korea to avoid acting in haste and "realize that returning to military tension and confrontation is a disgraceful path to death."
In summer 2000, the first meeting between the two Korean leaders took place in Pyongyang, which entailed a period of reconciliation. The second summit in the fall 2007 outlined ways to expand cooperation, but December's victory by Lee Myung-bak at presidential elections led to a revision of the country's foreign policy.
Certain foreign observers fear an aggravation in relations could complicate North Korean disarmament - a slowly advancing process involving diplomats from the two Koreas, Russia, the United States, China and Japan.
